During the last two decades the role of quantitative genetics in evolutionary theory has expanded considerably. Quantitative genetic-based models addressing long term phenotypic evolution, evolution in multiple environments (phenotypic plasticity) and evolution of ontogenies (developmental trajectories) have been proposed. Yet, the mathematical foundations of quantitative genetics were laid with a very different set of problems in mind (mostly the prediction of short term responses to artificial selection), and at a time in which any details of the genetic machinery were virtually (...) unknown. In this paper we discuss what a model is in population biology, and what kind of model we need in order to address the complexities of phenotypic evolution. We review the assumptions of quantitative genetics and its most recent accomplishments, together with the limitations that such assumptions impose on the modelling of some aspects of phenotypic evolution. We also discuss three alternative appr oaches to the theoretical description of evolutionary trajectories (nonlinear dynamics, complexity theory and optimization theory), and their respective advantages and limitations. We conclude by calling for a new theoretical synthesis, including quantitative genetics and not necessarily limited to the other approaches here discussed. (shrink)

Within the historical times, which roughly corresponds with the Holocene epoch, the whole of mankind is believed to be a single species. Homo sapiens. But the human genealogical tree is populated by a really astounding number of paleontological species and paleontological genera: Ardipithecus ramidus, Australopithecus anamensis, Australopithecus afarensis, Australopithecus africanus, Paranthropus robustus, Paranthropus boisei, Homo habilis, Homo georgicus. Homo erectus, Homo ergaster, Homo antecessor, Homo heidelbergensis, Homo neanderthalensis, Homo sapiens.. In fact there are many more but Foley, quite reasonably, states (...) that the evidence for their existence is, at present, insufficient. The existence of these multiple forms is beyond any doubt. The doubt, however arises concerning the human or „prehuman" status of them. Were they really true specific forms, half-way between the apes and Holocene man? Is it possible that they constitute a number of different ecotypes within the same natural species of Homo sapiens? (shrink)

Kluczowe w filozofii Lenartowicza było pojęcie organizmu żywego rozumianego jako cykl życiowy, który będąc powiązany z innymi podobnymi cyklami wplata się w sieć linii pokoleń danego rodzaju istot żywych. Fundamentem cyklu życiowego jest dynamika rozwojowa rozpoczynająca się w momencie poczęcia organizmu. Patrząc na osobnika z perspektywy jego rozwoju, można powiedzieć, że w swej najgłębszej istocie jest on nie tyle i nie przede wszystkim całościową funkcjonalną strukturą, która przejawia życie, ile jest raczej żywą dynamiką, której jednym z zasadniczych przejawów jest zintegrowane (...) budowanie, odbudowywanie, naprawianie i modyfikowanie różnorakich skorelowanych struktur ciała, czyli maszyn molekularnych, organelli i organów, które warunkują zachodzenie różnorodnych procesów biochemicznych i fizjologicznych oraz umożliwiają selektywne interakcje ze środowiskiem abiotycznym i biotycznym. (shrink)

We attempt to improve the understanding of the notion of agene being `for a phenotypic trait or traits. Considering theimplicit functional ascription of one thing being `for another,we submit a more restrictive version of `gene for talk.Accordingly, genes are only to be thought of as being forphenotypic traits when good evidence is available that thepresence or prevalence of the gene in a population is the resultof natural selection on that particular trait, and that theassociation between that trait and the gene (...) in question isdemonstrably causal. It is therefore necessary to gatherstatistical, biochemical, historical, as well as ecologicalinformation before properly claiming that a gene is for aphenotypic trait. Instead of hampering practical use of the `genefor talk, our approach aims at stimulating much needed researchinto the functional ecology and comparative evolutionary biologyof gene action. (shrink)

Many have argued that there is no reason why natural selection should cause directional increases in measures such as body size or complexity across evolutionary history as a whole. In this paper I argue that this conclusion does not hold for selection for adaptations to environmental variability, and that, given the inevitability of environmental variability, trends in adaptations to variability are an expected feature of evolution by natural selection. As a concrete instance of this causal structure, I outline how this (...) may be applied to a trend in phenotypic plasticity. (shrink)